This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A068225 #17 Jan 10 2021 02:17:56 %S A068225 2,11,12,3,4,1,8,9,10,27,28,29,30,13,14,15,16,5,6,7,22,23,24,25,26,51, %T A068225 52,53,54,55,56,31,32,33,34,35,36,17,18,19,20,21,44,45,46,47,48,49,50, %U A068225 83,84,85,86,87,88,89,90,57,58,59,60,61,62,63,64,37,38,39,40,41,42,43 %N A068225 Neighbor in 1-2 direction of numbers arranged as clockwise spiral. %H A068225 Peter Kagey, <a href="/A068225/b068225.txt">Table of n, a(n) for n = 1..10000</a> %H A068225 Frank Ellermann, <a href="/A068225/a068225.html">Some EIS sequences based on a spiral of natural numbers</a>. %H A068225 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>. %e A068225 For example, if the spiral is oriented such that 1 is immediately to the right of 2, as shown below, then a(2) = 11 because 11 is immediately to the right of 2. %e A068225 21--22--23--24--25--26 %e A068225 | | %e A068225 20 7---8---9---10 27 %e A068225 | | | | %e A068225 19 6 1---2 11 28 %e A068225 | | | | | %e A068225 18 5---4---3 12 29 %e A068225 | | | %e A068225 17--16--15--14--13 30 %e A068225 | %e A068225 36--35--34--33--32--31 %Y A068225 Cf. A068226 (inverse, left), A334751 (above), A334752 (below). %Y A068225 Cf. A054552 (middle row right), A054567 (middle row left). %K A068225 nonn,easy %O A068225 1,1 %A A068225 _Frank Ellermann_, Feb 22 2002